Solar cells have been developed in which the concentration of impurities is relatively high and the electrical resistance is relatively low below an electrode arranged on a light-receiving side, and the concentration of impurities is relatively low and the electrical resistance is relatively high below a section that receives light other than the section where the electrode is arranged. In the above solar cell, the electrical resistance that affects energy conversion is low, and recombination of electrons with positive holes on the light-receiving side is comparatively suppressed. Therefore, the solar cell can convert optical energy to power with high efficiency.
The solar cell has a selective emitter structure. Conventionally, a method using screen printing has been commonly known as a method to form a light-receiving-side electrode in the solar cell with a selective emitter structure. More specifically, as a method to detect a position of a light-receiving-side electrode to be formed by screen printing, it is common to use three points on an outer periphery of a semiconductor substrate as reference points to indirectly detect a position where a light-receiving-side electrode should be formed.
As a method to detect a position, there has been proposed a method in which a semiconductor substrate, formed with a high-concentration selective diffusion layer, is irradiated with light that passes through the semiconductor substrate to detect a position where a light-receiving-side electrode should be formed on the basis of an intensity distribution of the light having passed through the semiconductor substrate (see, for example, Patent Literature 1). There has also been proposed a method in which silicon nanoparticles are deposited on the surface of a semiconductor substrate, and the region of the silicon nanoparticles is irradiated with light to detect a position by using the reflectivity of the light (see, for example, Patent Literature 2).